Punch press with assembly locking mechanism

ABSTRACT

The die assembly is clamped to a die shoe by a locking arm which, when released, permits the assembly to be inserted into and removed from the shoe in a horizontal direction in order to avoid the vertical obstruction presented by a stripper overhanging the shoe. The arm is clamped and released by a vertically reciprocable rod carrying a pin which rides in an inclined slot in the arm to convert the vertical force exerted by the rod into a horizontally directed clamping force of relatively large magnitude.

United States Patent [191 Sawvell 1 Dec. 18, 1973 PUNCH PRESS WITHASSEMBLY LOCKING MECHANISM [75] Inventor: Roger V. Sawvell, New Milford,Ill.

[73] Assignee: W. A. Whitney Corp., Rockford, Ill. [22] Filed: July 24,1972 I I [2]] Appl. No.: 274,256

[52] US. Cl 83/698, 72/448, 100/DlG. l8, 100/224 [51] Int. Cl 326d 1/06[58] Field of Search 83/698, 523; 72/446, 72/447, 448; 100/DIG. 18, 224

[56] References Cited UNITED STATES PATENTS 2,984,176 5/1961 Sommer etal 83/698 3.559.522 2/1971 Valente 83/698 x 3,195,386 7/1965 Daniels83/698 X Primary Examiner-r-Andrew R. Juhasz Assistant Examiner-W. D.Bray Attorney-Wolfe, Hubbard, Leydig, Voit & Osann,

[ 5 7] ABSTRACT The die assembly is clamped to a die shoe by a lockingarm which, when released, permits the assembly to be inserted into andremoved from the shoe in a horizontal direction in order to avoid thevertical obstruction presented by a stripper overhanging the shoe. Thearm is clamped and released by a vertically reciprocable rod carrying apin which rides in an inclined slot in the arm to convert theverticalforce exerted by the rod into a horizontally directed clampingforce of rela tively large magnitude.

11 Claims, 6 Drawing Figures PATENTEB DEB I 8 I375 SHEEIIUFZ PUNCH PRESSWITH ASSEMBLY LOCKING MECHANISM BACKGROUND OF THE INVENTION Thisinvention relates to a punch press and, more particularly, to a punchpress with mechanism for locking a removable die assembly securely in adie shoe while a vertically reciprocable punch performs a punchingoperation on a workpiece located between the punch and the underlyingdie assembly. The latter SUMMARY OF THE INVENTION The general aim ofthepresent invention is to provide a punch press with a novel dieassembly locking mechanism which coacts with a uniquely constructed dieshoe to lock the die assembly securely in the shoe while permitting theassembly to be quickly and easily inserted into and removed from theshoe in a horizontal direction without obstruction from the overlyingstripper housing.

A more detailed object is to achieve the foregoing through the provisionof a locking mechanism with a locking arm which, when released from thedie assembly, is located below a radially extending slot in the die shoeso as to permit horizontal movement of the assem bly through the slotand into or out of the shoe.

Further objects of the invention are to provide comparatively simple,compact and durable actuating means for clamping and releasing thelocking arm and also to use the arm for effectively clamping the die tothe die adapter while simultaneously clamping the adapter tothe dieshoe.

The invention also resides in the novel construction of the die shoe tosecurely seat and accurately locate the die assembly around its entireperiphery and yet, at the same time, to enable removal of the assemblywithout need of moving the stripper housing.

These and other objects and advantages of the invention will become moreapparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THEDRAWINGS FIG'. 1 is a fragmentary elevationalview of a punch press embodying the novel features of the presentinvention, parts being broken away and shown in section.

FIG. 2 is a fragmentary view similar to FIG. 1 but showing certain partsin moved positions.

FIG. 3 is a fragmentary plan view of the die assembly and lockingmechanism and is taken along the line 3-3 of FIG. 1.

FIG; 4 is an enlarged fragmentary cross-section taken I substantiallyalong the line 4-4 of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in thedrawings for purposes of illustration, the invention is embodied in apunch press in which a punch 11 is rcciprocated upwardly and downwardlyand coacts with an underlying die 13 to form a hole in an interveningworkpiece (not shown) during each downstroke of the punch. Surroundingthe punch is a cylindrical stripper housing 14 whose lower end carriesan apertured stripper plate 15 which overlies the upper surface of theworkpiece.

During the punching operation, the stripper plate 15 always remains in afixed position and engages the workpiece on the upstroke of the punch 11thereby to strip the workpiece from the punch as the punch is retracted. In this particular instance, the minimum vertical clearancebetween the stripper plate and the die is approximately one-eighth inch,and, to accomodate workpieces of greater thicknesses, the stripperhousing 14 and plate 15 may be adjusted upwardlythrough a distance asmuch as five-eighths inch in essentially the same manner as disclosed inScott US. application Ser.

No. 168,099, now US. Pat. No. 3,720,125 filed Aug.

2, 1971 and assigned to the assignee of the present inwhose other mainpart is formed by a die adapter 17 which is usually matched to the dieand is sized and shaped to fit snugly but removably in a die shoe 19.The

latter is anchored by screws 20 (FIG. 3) to a flat bolster plate 21(FIG. 1) which, in turn, is anchored rigidly to the bed 23 or mainsupport of the press. Slugs punched from the workpiece are removed fromthe die through a vertically extending slug chute 24 extending throughthe die adapter, the die shoe and the bolster plate.

More specifically, the upper end of the die shoe 19 is formed with agenerally circular and upwardly opening recess in the form of acounterbore 25 whose side and bottom walls are precisely finished anddefine a seat into which the die adapter 17 is removably telescoped andaccurately located. A generally similar counterbore 26 is formed in thedie adapter 17 and receives and accurately locates the die 13. Toprevent the adapter 17 from turning relative to the shoe 19, an upwardlyopening and radially extending keyway 27 is formed through the rear sidewall of the counterbore 25 and slidably but snugly receives a rigid key29 projecting outwardly from the rear of the adapter. A cylindrical key30 extends slidably through the front wall of the counterbore 26 in theadapter and seats at its inner end in a downwardly and forwardlyinclined notch 31 formed in the front of the die. A. coiled compressionspring 33 (FIG. I) is telescoped into a hole 34 drilled in the upperside of the adapter and fits into a flatbottomed notch 35 on theunderside of the key 30 to permit radial sliding of the latter through alimited distance out of the notch 31 while retaining the key in theadapter.

In accordance with the present invention, provision is made of a novellocking mechanism 37 for clamping the die assembly 16 tightly within theshoe 19 but capable of permitting removal of the assembly from the shoein a substantially horizontal direction to that such removal can beeffected quickly and easily in spite of the obstruction presented by theoverlying stripper housing 14 without need of moving the housing to increase the yertical clearance above the die assembly.

For these purposesjthe locking mechanism includes a locking arm 39 whichclamps the die assembly when disposed in a locked position shown in FIG.1 and which, upon being moved to a released position shown in FIG. 2, isdisposed below the bottom 40 of a radially extending slot 41 in thecounterbore 25 of the die shoe 19 so as to permit horizontal removal ofthe die assembly through the slot and across the arm. Thus, the dieassembly can be removed quickly and easily from the shoe in spite of thelimited vertical clearance between the die 13 and the stripper housing14 and, by the same token, a different die assembly can be easily loadedinto the shoe.

More particularly, the slot 41 in the die shoe 19 opens upwardly andextends radially through the front wall of the counterbore 25, has awidth just slightly greater than the diameter of the counterbore, andpreferably is formed with a depth which is somewhat less than the depthof the counterbore. The difference between the depth of the slot 41 andthe depth of the counterbore 25 is just slightly less than the minimumvertical clearance between the die 13 and the stripper housing 14 and,in this particular instance, is thus just slightly less than one-eighthinch. As a result of the depth of the slot, a short vertical portion 43(FIG. 2) of the front wall of the counterbore 25 is left intact aroundand below the slot to pilot and locate the die adapter 17 and yet theadapter can be. lifted vertically to the level of the bottom 40 of theslot and then moved horizontally through the slot and out of the shoe19.

The locking arm 39 is located forwardly of and is centered relative tothe slot 41 (see FIGS. 1 and 3) and is formed by an upper nose 45 (FIG.which extends across and is joined to a pair of horizontally spaced andvertically extending plates 46. The latter straddle an upstandingsupport block 47 fitted in a hole 49 (FIG. 1) in the bolster plate 21and bolted to a mounting strip 50 secured to the underside of thebolster plate. A sheet metal housing 51 secured to the bolster plateencloses the support block 47 and includes a top wall formed with anupwardly opening slot 53 through which the locking arm projects when thelatter is in its locked positionshown in FIG. 1. The nose 45 of thelocking arm is retracted into the housing and is spaced below the top ofthe housing when the locking arm is in its released position shown inFIG. 2.

As shown in FIGS. 1 and 5, a horizontal pivot pin 55 is locatedforwardly of and below the slot 41 and extends through the plates 46 andthe support block 47 to mount the locking arm 39 for swinging betweenits locked and released positions. To swing the arm between suchpositions, a pneumatic cylinder 56 (FIG. 1) is supported on theunderside of the mounting strip 50 and includes a verticallyreciprocable rod 57 which extends upwardly through a vertical hole 59(FIG. 5) in the support block 47. A horizontal pin 60 is carried on theupper end portion of the rod and extends snugly but slidably through avertical slot 61 in the block and through inclined slots 63 formed inthe plates 46, the slots 63 extending across the slot 61 and extendingsubstantially horizontally when the arm is disposed in its releasedposition shown in FIG. 2.

When the rod 57 is extended upwardly by actuating the cylinder 56, thepin 60 rides upwardly in the vertical slot 61 and cams against the upperedges of the slots 63 to swing thelocking arm 39 upwardly about the pin55 toward the locked position shown in FIG. 1. As the arm approaches thelocked position, the nose 45 engages the outer end of the key 30 andforces the latter inwardly against the bottom of the notch 31. The freeend 65 of the nose is inclined downwardly and forwardly and thus thenose exerts a downwardly and rearwardly directed force on the key. Suchforce acts through the die 13 to crowd and clamp the die adapter 17downwardly and rearwardly against the bottom and rear walls of thecounterbore 25 and, at the same time, acts on the die to crowd and clampthe latter downwardly and rearwardly against the bottom and rear wallsof the counterbore 26.

When the locking arm 39 is in its locked position, the slots 63 in thearm are inclined upwardly and outwardly relative to the rod 57 at anangle of about 10 and, as a result, the force exerted on the rear edgeof the slots by the pin 60 includes a horizontal component of relativelylarge magnitude for passing the nose 45 against the key 30. Also, thereaction force on the locking arm is transmitted by the pin 60 to theedges of the vertical slot 61 in the support block 49 and thus suchforce is ultimately resisted by the bed 23 of the press rather thanimposing bending stresses on the rod 57 of the cylinder 56. Accordingly,the unique arrangement of the slots 61 and 63 enables effectiveactuation of the arm 39 with the vertically movable pin 60 and alsoavoids the exertion of bending stresses on the rod 57 and the cylinder56.

During the punching operation, the die 13 is anchored rigidly within thedie adapter 17 and the latter is clamped tightly to the die shoe 19 bythe locking arm 39. When the tooling is to be changed, the adapter isunclamped from the shoe and both the adapter and the die (i.e., the dieassembly 16) are removed from the shoe as a unit and replaced with adifferent die assem- To remove the die assembly 16 from the shoe 19, therod 57-is shifted downwardly to swing the locking arm 39 downwardly tothe released position shown in FIG. 2. In this position, the entire armis disposed below the horizontal plane containing the bottom 40 of theslot 41 in the shoe. Accordingly, the die assembly may be removed fromthe shoe by first lifting the assembly vertically a slight distance toclear the short portion 43 of the front wall of the counterbore 25 andthen by moving the assembly forwardly and horizontally beneath thestripper housing 14, through the slot 41 and across the retractedlocking arm 39 (see FIG. 2). A new assembly may be inserted into theshoe by following the same steps in reverse order and thus changing ofthe disc assemblies may be effected quickly and easily in spite of theobstruction presented by the overhanging stripper housing 14.

From the foregoing, it will be apparent that the present inventionbrings to the art a new and improved mechanism 37 for effectivelylocking the die assembly 16 to the die shoe 19 while permitting theassembly to be moved horizontally between the shoe and the stripperhousing 14 when inserted into or removed from the shoe. As a result ofactuating the clamping arm 39 with the pin 60 movable vertically in theslots 61 and 63, the mechanism 37 is of comparatively simple and compactconstruction and yet is relatively durable and troublefree dur ingservice use.

I claima mxiayentbw 1. A punch press having a support, a die shoeattached to said support and formed with an upwardly opening recessdefining a seat, and a die assembly telescoped removably into said seatand projecting upwardly from said shoe, the improvement in said presscomprising, an upwardly opening and radially extending slot formedthrough one wall of said recess and having a width at least equal to thediameter of the recess, a locking arm, and means mounting said arm onsaid support for upward and downward movement between;

a. a locked position in which the arm extends upwardly alongside saidslot and engages the die as sembly to clamp the latter to said die shoe,and

b. a released position in which the arm is disengaged from said dieassembly and is spaced below the upper end of said slot to permitremoval of the die assembly from the recess in the shoe by moving theassembly generally horizontally out of said slot and a9r9 sais1. rm-.. sa. H t

2. A punch press having a support, a die shoe attached to said supportand formed with an upwardly opening counterbore, and a die assemblytelescoped removably into said counterbore and projecting upwardly fromsaid shoe, the improvement in said press comprising, an upwardly openingand radially extending slot formed through one wall of said counterboreand having a width at least equal to the diameter of the counterbore, alocking arm mounted on said support to swing upwardly and downwardlyabout a generally horizontal axis located outwardly of and below saidslot, and means connected to said arm for swinging the lattu war y a iqsnward QWQQF EPQQWEQ? a. a locked position in which the arm engages thedie assembly and clamps the latter to said die shoe, and

b. a released position in which the arm is disengaged from said dieassembly and is spaced below the bottom of said slot to permit removalof the die assembly from the shoe by moving the assembly generallyhorizontally across the bottom of the slot and ossns darm-hr .7 a

3. A punch press as defined in claim 2 in which the depth of said slotis slightly less than the depth of the counterbore whereby the entireperiphery of said die assembly is seated in said counterbore but saidassembly may be removed from said shoe by lifting the assembly to thelevel of the bottom of the slot and then moving the assembly generallyhorizontally across the bottom of the slot.

4. A punch press as defined in claim 2 further including an elongatedand generally vertical slot formed in said support and spaced from saidaxis, an elongated slot formed through said locking arm and crossingsaid vertical slot, said means comprising a pin slidably mounted withinsaid elongated slots, and mechanism for reciprocating said pin upwardlyand downwardly within said vertical slot.

5. A punch press as defined in claim 4 in which said slot in saidlocking arm is located so as to slant upwardly and outwardly when saidarm is in said locked.

position fi A pungh press as defined in claim 5 in which said allyhorizontally when said arm is in said released position.

7. A punch press having a support, a die shoe attached to said supportand formed with a first upwardly opening counterbore, a die adaptertelescoped removably into said first counterbore and formed with asecond upwardly opening counterbore. a die telescoped removably intosaid second counterbore, and a radially extending key mounted slidablyin the side wall of said second counterbore and having an inner endengageable with the outer side of said die, the improvement in saidpress comprising, an upwardly opening and radially extending slot formedthrough. one wall of said first counterbore and having a width at leastequal to the diameter of such counterbore, a locking arm mounted on saidsupport to swing about a generally horizontal axis located outwardly ofand below said slot, an elongated vertical slot formed in said supportand located outwardly of said axis, an elongated slot formed throughsaid locking arm and crossing said vertical slot, a pin slidably mountedwithin said elongated slots, and means for reciprocating said pinvertically to swing said locking arm upwardly and downwardly about saidaxis b ts t y t a. a locked position in which the free end of the armpresses against the outer end of said key to clamp said die into saidsecond counterbore and to clamp said die adapter into said firstcounterbore, and

b. a released position in which the arm is disengaged from said key andis spaced below the upper surface of said die shoe to permit removal ofthe die adapter from the shoe by moving the adapter generallyhorizontally across the bottom of said radially extending slot andacross said arm.

8. A punch press as defined in claim 7 in which the depth of saidradially extending slot is slightly less than the depth of said firstcounterbore whereby the entire periphery of said die adapter is seatedin said first counterbore but said adapter may be: removed from saidshoe by lifting the adapter to the level of the bottom of said radiallyextending slot and then moving the adapter generally horizontally acrossthe bottom of said radially extending slot.

9. A punch press as defined in claim 7 in which the free end of said armis inclined downwardly and outwardly when said arm is in said lockedposition and acts through said key to force said die radially anddownwardly against the side and bottom walls, respectively, of saidsecond counterbore and to force said die adapter radially and downwardlyagainst the side and bottom walls, respectively, of said firstcounterbore.

10. A punch press as defined in claim 7 in which said slot in saidlocking arm is located so as to slant upwardly and outwardly when saidarm is in said locked position.

11. A punch press as defined in claim 10 in which said slot in saidlocking arm is located so as to extend generally horizontally when saidarm is in said released position.

1. A punch press having a support, a die shoe attached to said supportand formed with an upwardly opening recess defining a seat, and a dieassembly telescoped removably into said seat and projecting upwardlyfrom said shoe, the improvement in said press comprising, an upwardlyopening and radially extending slot formed through one wall of saidrecess and having a width at least equal to the diameter of the recess,a locking arm, and means mounting said arm on said support for upwardand downward movement between: a. a locked position in which the armextends upwardly alongside said slot and engages the die assembly toclamp the latter to said die shoe, and b. a released position in whichthe arm is disengaged from said die assembly and is spaced below theupper end of said slot to permit removal of the die assembly from therecess in the shoe by moving the assembly generally horizontally out ofsaid slot and across said arm.
 2. A punch press having a support, a dieshoe attached to said support and formed with an upwardly openingcounterbore, and a die assembly telescoped removably into saidcounterbore and projecting upwardly from said shoe, the improvement insaid press comprising, an upwardly opening and radially extending slotformed through one wall of said counterbore and having a width at leastequal to the diameter of the counterbore, a locking arm mounted on saidsupport to swing upwardly and downwardly about a generally horizontalaxis located outwardly of and below said slot, and means connected tosaid arm for swinging the latter upwardly and downwardly about said axisbetween: a. a locked position in which the arm engages the die assemblyand clamps the Latter to said die shoe, and b. a released position inwhich the arm is disengaged from said die assembly and is spaced belowthe bottom of said slot to permit removal of the die assembly from theshoe by moving the assembly generally horizontally across the bottom ofthe slot and across said arm.
 3. A punch press as defined in claim 2 inwhich the depth of said slot is slightly less than the depth of thecounterbore whereby the entire periphery of said die assembly is seatedin said counterbore but said assembly may be removed from said shoe bylifting the assembly to the level of the bottom of the slot and thenmoving the assembly generally horizontally across the bottom of theslot.
 4. A punch press as defined in claim 2 further including anelongated and generally vertical slot formed in said support and spacedfrom said axis, an elongated slot formed through said locking arm andcrossing said vertical slot, said means comprising a pin slidablymounted within said elongated slots, and mechanism for reciprocatingsaid pin upwardly and downwardly within said vertical slot.
 5. A punchpress as defined in claim 4 in which said slot in said locking arm islocated so as to slant upwardly and outwardly when said arm is in saidlocked position.
 6. A punch press as defined in claim 5 in which saidslot in said locking arm is located so as to extend generallyhorizontally when said arm is in said released position.
 7. A punchpress having a support, a die shoe attached to said support and formedwith a first upwardly opening counterbore, a die adapter telescopedremovably into said first counterbore and formed with a second upwardlyopening counterbore, a die telescoped removably into said secondcounterbore, and a radially extending key mounted slidably in the sidewall of said second counterbore and having an inner end engageable withthe outer side of said die, the improvement in said press comprising, anupwardly opening and radially extending slot formed through one wall ofsaid first counterbore and having a width at least equal to the diameterof such counterbore, a locking arm mounted on said support to swingabout a generally horizontal axis located outwardly of and below saidslot, an elongated vertical slot formed in said support and locatedoutwardly of said axis, an elongated slot formed through said lockingarm and crossing said vertical slot, a pin slidably mounted within saidelongated slots, and means for reciprocating said pin vertically toswing said locking arm upwardly and downwardly about said axis between:a. a locked position in which the free end of the arm presses againstthe outer end of said key to clamp said die into said second counterboreand to clamp said die adapter into said first counterbore, and b. areleased position in which the arm is disengaged from said key and isspaced below the upper surface of said die shoe to permit removal of thedie adapter from the shoe by moving the adapter generally horizontallyacross the bottom of said radially extending slot and across said arm.8. A punch press as defined in claim 7 in which the depth of saidradially extending slot is slightly less than the depth of said firstcounterbore whereby the entire periphery of said die adapter is seatedin said first counterbore but said adapter may be removed from said shoeby lifting the adapter to the level of the bottom of said radiallyextending slot and then moving the adapter generally horizontally acrossthe bottom of said radially extending slot.
 9. A punch press as definedin claim 7 in which the free end of said arm is inclined downwardly andoutwardly when said arm is in said locked position and acts through saidkey to force said die radially and downwardly against the side andbottom walls, respectively, of said second counterbore and to force saiddie adapter radially and downwardly against the side and bottom walls,respectively, of said first counterbore.
 10. A punch press as defined inclaim 7 in which said slOt in said locking arm is located so as to slantupwardly and outwardly when said arm is in said locked position.
 11. Apunch press as defined in claim 10 in which said slot in said lockingarm is located so as to extend generally horizontally when said arm isin said released position.